1. Field of the Invention
This invention relates broadly to natural gas power plants. More particularly, this invention relates to power plants which utilize natural gas recovered from gas fields and which generate power with no atmospheric emissions of greenhouse gases due to sequestration of carbon dioxide by-products. The power plants of the invention can provide pure liquid natural gas (LNG) and/or hydrogen gas as a desired output.
2. State of the Art
Global warming and its potential impact on earth's climate, ocean levels and human lifestyles are active areas of research and discussion. While there is some debate over the causes of global warming, there is unequivocal data that the atmospheric levels of greenhouse gases, which include carbon dioxide (CO2) are rising rapidly. Carbon dioxide levels in the earth's atmosphere are at historic high levels. Although the greenhouse warming potential of carbon dioxide is small compared to some of the other greenhouse gases, due to the sheer mass of carbon dioxide emitted into the atmosphere, carbon dioxide presently has the highest impact of any greenhouse gas in the atmosphere.
It is estimated that globally, over 24 billion metric tons (tonnes) of carbon dioxide were emitted into the earth's atmosphere in 2001 as a result of burning fossil fuels. Some predict that by the year 2025, global emissions of carbon dioxide may reach 35 billion tonnes. It is clear that technological solutions to improved energy solutions that reduce greenhouse gas emissions need to be researched, engineered and implemented. It is also clear that no large-scale replacement or substitution for fossil fuels is likely to appear in the very short term. However, if it is possible to capture and store (or sequester) a significant amount of carbon dioxide released into the atmosphere, the potential impact of carbon dioxide on global warming may be limited. The sequestration process is also likely to provide additional time for society to research and engineer alternative energy solutions.
Geological formations such as saline aquifers, abandoned oil and gas fields, and coal bed methane reservoirs are the leading candidates for long term storage of carbon dioxide. Efforts are underway to identify suitable geological sites for carbon dioxide sequestration close to industrial areas that release a high amount of carbon dioxide into the atmosphere (e.g., the Mountaineer Plant in the Ohio river valley, West Virginia, the South Liberty Oil field near Houston, Tex., etc.). Proximity of a sequestration site to a large source of carbon dioxide is desirable to avoid the high transport costs of pumping carbon dioxide over large distances. This invention considers sequestration of carbon dioxide close to the power plant to minimize transportation costs.